1. Field of the Invention
This invention relates to packet data networks and is in particular but not necessarily related to authentication and billing of a mobile station connecting to a mobile IP (Internet Protocol) network.
2. Description of the Prior Art
For authenticating in the Internet, a shared secret must first be provided both to the packet data network as well as to the mobile node so that the secret can be used as a basis for authentication. Then, some authentication procedure has to be executed in order to authenticate a node to another node.
RADIUS (Remote Authentication Dial In User Service) is an Internet standards track protocol described in a memo rfc2138.txt, April 1997, by C. R. Livingston, A R. Merit, W. S. Daydreamer, and S. W. Livingston. The RADIUS protocol is designed for carrying authentication information, authorization information and configuration information between a Network Access Server which desires to authenticate its links and a shared Authentication server. Servers implementing RADIUS can support a variety of user authentication methods. When the server is provided with a user name and original password given by a user, it can support the Point-To-Point Protocol (PPP), the Password Authentication Protocol (PAP), the Challenge Handshake Authentication Protocol (CHAP), UNIX login and other authentication mechanisms.
A memo rfc2139.txt, April 1997, by C. R. Livingston deals with RADIUS accounting. Here, the RADIUS protocol is used to carry accounting information between a Network Access Server and a shared Accounting Server.